Duodenal carcinoids in patients with and without neurofibromatosis. A comparative study.

Nine duodenal carcinoids from patients with von Recklinghausen's neurofibromatosis (VRNF) were investigated for their morphologic, immunocytochemical, and ultrastructural characteristics, and were compared with seven similar tumors from patients without VRNF. Strong similarities were found between tumors in each group. Irrespective of their association with VRNF, duodenal carcinoids arose in adults and usually produced jaundice, upper intestinal bleeding, or obstruction. Tumors larger than 2.0 cm had already metastasized when first detected. All tumors showed a mixed architectural pattern; five tumors associated with VRNF were of the psammomatous type, as opposed to two of those without VRNF. While no tumors showed argentaffinity, stray argyrophil cells were present only in the three tumors not associated with VRNF. All of the tumors showed immunocytochemical evidence of somatostatinomas, and only one VRNF-associated tumor showed immunoreactivity for an additional regulatory substance, as opposed to three of those not associated with VRNF. Thus, while VRNF-associated duodenal carcinoids are not otherwise distinctive, they tend to be pure somatostatinomas (eight of nine cases), whereas similar tumors unassociated with VRNF are frequently multihormonal (three of seven cases). While many more duodenal carcinoids need to be investigated systematically for their immunocytochemical profile, detection of a pure somatostatinoma in the duodenum should alert one to the possibility of coexistent VRNF.